SPRAYING MACHINE

Abstract

Injection molding machine (10), comprising: a mold closing / clamping motor (160) that moves a mold closing / clamping unit (100) to perform mold closing / clamping of a mold unit (800); a drive unit (721) that supplies power to the form-closing / clamping motor (160); a changeover switch (730) provided in a wire (722) connecting the mold closing / clamping motor (160) and the drive unit (721), which is capable of switching between supplying and stopping the current from the drive unit (721) to the mold closing / clamping motor (160), and which is capable of switching between not activating a brake of the mold closing / clamping motor (160) and activating the brake; and a digital circuit (711) connected to the changeover switch (730) and controlling the changeover switch (730), wherein the digital circuit (711) controls the changeover switch (730) based on the detection of a trigger signal to stop the mold closing / clamping motor (160) in order to perform the feed stop and activation of the brake, the digital circuit (711) controls the feed stop of the switch (730) and the activation of the brake after waiting for a waiting period that is set from the time at which the trigger signal is detected, and The waiting time is set to be equal to or longer than the time in which pressure relief is completed from a state in which the forming unit (800) is pressed by the forming closing / clamping unit (100).

Description

BACKGROUND OF THE INVENTION Area of ​​the invention

[0001] The present disclosure relates to an injection molding machine.

[0002] The present application claims priority on the basis of Japanese patent application No. 2023-087901, filed on May 29, 2023, the entire contents of which are incorporated herein by reference. Description of the state of the art

[0003] During injection molding on an injection molding machine, there is a possibility that a user might open a safety door of a housing covering a mold clamping unit or similar device. For the user's safety, the injection molding machine's control system automatically stops the drive of a mold clamping motor or similar device if the safety door is opened during injection molding.

[0004] For example, JP 4 460 540 B2 discloses an injection molding machine comprising a safety door, a detection unit that detects whether the safety door is open or closed, and a control unit that stops a drive unit based on a detection result from the detection unit. In the injection molding machine's control unit, a switch is toggled when the safety door is opened, thus de-energizing a coil of a relay switch that actuates a motor drive unit of a mold closing / clamping mechanism, thereby stopping the drive unit.

[0005] Furthermore, DE 10 2018 006 023 A1 discloses a brake control method for an injection molding machine in which the power supply to a servo motor is switched off and a brake mechanism is actuated. DE 101 42 041 A1 describes an injection molding machine with a door whose opening, triggered by actuating a safety switch, interrupts the power supply to the electric motor. Another brake control method for an injection molding machine is described in JP 2013-014 054 A. SUMMARY OF THE INVENTION

[0006] In the injection molding machine disclosed in JP 4 460 540 B2, a circuit connecting a safety door switch to a relay switch for switching off the power to the motor drive unit is linked via an analog circuit. In this case, a large variation in the stopping time of the motor drive unit can occur due to variations in parts of the analog circuit (variation in capacitor capacitance, resistance, or the like) or environmental factors (temperature, voltage value, or the like).

[0007] The present disclosure provides an injection molding machine that is capable of accurately controlling the timing of stopping a mold closing / clamping motor.

[0008] The problem described above is solved by an injection molding machine according to claim 1. According to one aspect of the present disclosure, an injection molding machine is provided comprising a mold closing / clamping motor that moves a mold closing / clamping unit to perform mold closing / clamping of a mold unit, a drive unit that supplies current to the mold closing / clamping motor, a changeover switch provided in a wire connecting the mold closing / clamping motor and the drive unit, which is capable of switching between supplying and stopping the supply of current from the drive unit to the mold closing / clamping motor, and which is capable of switching between not activating a brake of the mold closing / clamping motor and activating the brake, and a digital circuit connected to the changeover switch that controls the changeover switch.the digital circuit controls the switch based on the detection of a trigger signal to stop the mold closing / clamping motor in order to perform the feed stop and brake activation.

[0009] According to this aspect, it is possible to accurately control the stopping point of a form-closing / clamping motor. BRIEF DESCRIPTION OF THE FIGURES Fig. Figure 1 is a diagram showing the state of an injection molding machine according to an embodiment at the point of completion of mold opening. Fig. Figure 2 is a diagram showing a state of the injection molding machine according to the embodiment at a time of mold closing / clamping. Fig. Figure 3 is a diagram showing a main configuration of a power supply circuit for a form-closing / clamping motor and a control board. Fig. Figure 4 is a block diagram showing functional blocks of a control device and a safety PLC. Fig. Figure 5 is a timing diagram showing an operating procedure when the safety PLC stops the form-closing / clamping motor. DETAILED DESCRIPTION OF THE INVENTION

[0010] Embodiments of the present disclosure are described below with reference to the drawings. The same components are designated by the same reference numerals in the respective drawings, and the repeated description thereof is omitted. (Injection molding machine)

[0011] Fig. Figure 1 is a diagram showing the state of an injection molding machine according to an embodiment at the time of completion of mold opening. Fig. Figure 2 is a diagram showing a state of the injection molding machine according to the embodiment at the time of mold closing / clamping. In this description, the X-axis, Y-axis, and Z-axis directions are mutually perpendicular. The X-axis and Y-axis directions indicate horizontal directions, and the Z-axis direction indicates a vertical direction. In a case where a mold closing / clamping unit 100 is of a horizontal type, the X-axis direction is a mold opening / closing direction, and the Y-axis direction is a width direction of an injection molding machine 10. A negative side in the Y-axis direction is referred to as an operator side, and a positive side in the Y-axis direction is referred to as a counter-operator side.

[0012] As in Fig. 1 and Fig. As shown in Figure 2, the injection molding machine 10 includes a mold clamping unit 100 that opens and closes a mold unit 800, an ejector unit 200 that ejects molded products formed by the mold unit 800, an injection unit 300 that injects molding material into the mold unit 800, a motion unit 400 that causes the injection unit 300 to move back and forth relative to the mold unit 800, a control device 700 that controls the respective components of the injection molding machine 10, and a frame 900 that supports the respective components of the injection molding machine 10. The frame 900 includes a mold clamping unit frame 910 that supports the mold clamping unit 100, and an injection unit frame 920 that supports the injection unit 300. The form-closing / clamping unit frame 910 and the injection unit frame 920 are each installed on a floor 2 via height adjuster 930.The control device 700 is arranged in an interior space 922 of the injection unit frame 920. The respective components of the injection molding machine 10 are described below. (Form-fit / clamping unit)

[0013] In the description of the mold closing / clamping unit 100, a direction of movement of a movable plate 120 in a case where a mold is to be closed (for example, a positive X-axis direction) corresponds to a front side, and a direction of movement of the movable plate 120 in a case where the mold is to be opened (for example, a negative X-axis direction) corresponds to a back side.

[0014] The mold closing / clamping unit 100 performs mold closing, pressurization, mold closing / clamping, pressure release, and mold opening of the mold unit 800. The mold unit 800 contains a stationary mold 810 and a movable mold 820.

[0015] The mold closing / clamping unit 100, for example, is of a horizontal type, and the mold opening / closing direction of the mold closing / clamping unit 100 is a horizontal direction. The mold closing / clamping unit 100 comprises a stationary plate 110 to which the stationary mold 810 is attached, the movable plate 120 to which the movable mold 820 is attached, and a movement mechanism 102 that moves the movable plate 120 relative to the stationary plate 110 in the mold opening / closing direction.

[0016] The stationary plate 110 is attached to the form-closing / clamping unit frame 910. The stationary form 810 is attached to a surface of the stationary plate 110 that faces the movable plate 120.

[0017] The movable plate 120 is arranged so that it is movable in the mold opening / closing direction relative to the mold closing / clamping unit frame 910. Guides 101, which guide the movable plate 120, are placed on the mold closing / clamping unit frame 910. The movable mold 820 is attached to a surface of the movable plate 120 that faces the stationary plate 110.

[0018] The movement mechanism 102 causes the movable plate 120 to move back and forth relative to the stationary plate 110 in order to perform mold closing, pressurization, mold closing / clamping, pressure relief and mold opening of the mold unit 800. The motion mechanism 102 includes a toggle lever carrier 130, which is arranged with a distance between the stationary plate 110 and itself, columns 140 that connect the stationary plate 110 to the toggle lever carrier 130, a toggle lever mechanism 150 that moves the movable plate 120 relative to the toggle lever carrier 130 in the mold opening / closing direction, a mold closing / clamping motor 160 that actuates the toggle lever mechanism 150, a motion conversion mechanism 170 that converts a rotary motion of the mold closing / clamping motor 160 into a linear motion, and a mold space adjustment mechanism 180 that adjusts a distance between the stationary plate 110 and the toggle lever carrier 130.

[0019] The toggle lever carrier 130 is positioned at a distance between itself and the stationary plate 110 and is placed on the mold closing / clamping unit frame 910 such that it is movable in the mold opening / closing direction. The toggle lever carrier 130 can be arranged to move along guides that are placed on the mold closing / clamping unit frame 910. The guides for the toggle lever carrier 130 can be shared with the guides 101 for the movable plate 120.

[0020] In the present embodiment, the stationary plate 110 is attached to the mold closing / clamping unit frame 910, and the toggle lever support 130 is arranged so that it is movable relative to the mold closing / clamping unit frame 910 in the mold opening / closing direction. However, the toggle lever support 130 can also be attached to the mold closing / clamping unit frame 910, and the stationary plate 110 can be arranged so that it is movable relative to the mold closing / clamping unit frame 910 in the mold opening / closing direction.

[0021] The columns 140 connect the stationary plate 110 to the toggle lever support 130 at a distance L between the stationary plate 110 and the toggle lever support 130 in the mold opening / closing direction. Several columns 140 (for example, four) can be used. The multiple columns 140 are arranged parallel to the mold opening / closing direction and extend depending on a mold closing / clamping force. At least one column 140 can be equipped with a column strain detector 141, which measures the strain of the column 140. The column strain detector 141 sends a signal indicating a detection result to the control device 700. The detection result of the column strain detector 141 can be used for measuring a mold closing / clamping force and the like.

[0022] In the present embodiment, the column strain gauge 141 is used as a form-closing / clamping force detector for detecting a form-closing / clamping force, but the present invention is not limited to this. The form-closing / clamping force detector is not limited to one type of strain gauge and can be of a piezoelectric, capacitive, hydraulic, electromagnetic, or the like. The position at which the form-closing / clamping force detector is mounted is also not limited to the column 140.

[0023] The toggle mechanism 150 is arranged between the movable plate 120 and the toggle support 130 and moves the movable plate 120 relative to the toggle support 130 in the mold opening / closing direction. The toggle mechanism 150 includes a crosshead 151, which moves in the mold opening / closing direction, and a pair of link groups that are flexed and extended depending on the movement of the crosshead 151. Each pair of link groups includes a first link 152 and a second link 153, which are flexibly and flexibly connected to each other by a pin or the like. The first link 152 is oscillatingly attached to the movable plate 120 by a pin or the like. The second link 153 is oscillatingly attached to the toggle support 130 by a pin or the like. The second connecting link 153 is attached to the crosshead 151 via a third connecting link 154.In a case where the crosshead 151 is caused to move forward and backward with respect to the toggle support 130, the first and second connecting links 152 and 153 are flexed and extended, and the movable plate 120 moves forward and backward with respect to the toggle support 130.

[0024] The configuration of the toggle lever mechanism 150 is not limited to the configuration shown in Fig. 1 and Fig. 2 is shown. Fig. 1 and Fig. 2 is the number of nodes in each link group, for example five, but it can be four. An end section of the third link 154 can be connected to the node between the first and second links 152 and 153.

[0025] The form-locking / clamping motor 160 is attached to the toggle lever carrier 130 and actuates the toggle lever mechanism 150. The form-locking / clamping motor 160 causes the crosshead 151 to move back and forth relative to the toggle lever carrier 130, so that the first and second connecting links 152 and 153 are flexed and extended, causing the movable plate 120 to move back and forth relative to the toggle lever carrier 130. The form-locking / clamping motor 160 is directly connected to the motion conversion mechanism 170, but can also be connected to the motion conversion mechanism 170 via a belt, pulleys, and the like.

[0026] The motion conversion mechanism 170 converts a rotary motion of the form-closing / clamping motor 160 into a linear motion of the crosshead 151. The motion conversion mechanism 170 includes a spindle shaft and a spindle nut that is screwed onto the spindle shaft.

[0027] Balls or rollers may be inserted between the spindle shaft and the spindle nut.

[0028] The mold closing / clamping unit 100 performs a mold closing process, a pressurization process, a mold closing / clamping process, a pressure relief process, a mold opening process and the like under the control of the control device 700.

[0029] In the mold closing process, the mold closing / clamping motor 160 is driven to cause the crosshead 151 to move forward at a set speed to a mold closing position, causing the moving plate 120 to move forward and the moving mold 820 to contact the stationary mold 810. The position and speed of the crosshead 151 are measured, for example, using a mold closing / clamping motor encoder 161 or the like. The mold closing / clamping motor encoder 161 measures the rotation of the mold closing / clamping motor 160 and sends a signal indicating a detection result to the control device 700.

[0030] A crosshead position detector for measuring the position of the crosshead 151 and a crosshead velocity detector for measuring the velocity of the crosshead 151 are not limited to the form-closing / clamping motor encoder 161, and general detectors can be used. Furthermore, a moving plate position detector for measuring the position of the moving plate 120 and a moving plate velocity detector for measuring the velocity of the moving plate 120 are not limited to the form-closing / clamping motor encoder 161, and general detectors can be used.

[0031] During the pressurization process, the mold closing / clamping motor 160 is driven further to cause the crosshead 151 to move forward from the mold closing end position to a mold closing / clamping position and to generate a mold closing / clamping force.

[0032] During the mold closing / clamping process, the mold closing / clamping motor 160 is driven to maintain the position of the crosshead 151 in the mold closing / clamping position. The mold closing / clamping force generated during the pressurization process is maintained during the mold closing / clamping process. During the mold closing / clamping process, cavity spaces 801 are located between the moving mold 820 and the stationary mold 810 (see figure). Fig. 2) formed, and the injection unit 300 fills the cavity spaces 801 with liquid molding material. Molded products are obtained when the molding material filling the cavity spaces has solidified.

[0033] One cavity 801 can be provided, or several cavity 801s can be provided. In the latter case, several molded products are obtained simultaneously. A filling material can be arranged in one part of each cavity 801, and the other part of each cavity 801 can be filled with a molding material. Molded products in which the filling material and the molding material are integrated are obtained.

[0034] During the pressure relief process, the mold closing / clamping motor 160 is driven to cause the crosshead 151 to move backward from the mold closing / clamping position to a mold opening start position, thus causing the moving platen 120 to move backward to reduce the mold closing / clamping force. The mold opening start position and the mold closing end position can be the same position.

[0035] During the mold opening process, the mold closing / clamping motor 160 is driven to cause the crosshead 151 to move backward at a set speed from the mold opening start position to a mold opening end position, causing the moving platen 120 to move backward and separating the moving mold 820 from the stationary mold 810. The ejector unit 200 then ejects the molded products from the moving mold 820.

[0036] Setting conditions for the mold closing process, the pressurization process, and the mold closing / clamping process are collectively set as a set of setting conditions. For example, the movement speeds and positions (including a mold closing start position, a movement speed change position, a mold closing end position, and a mold closing / clamping position) of the crosshead 151 and the mold closing / clamping forces for the mold closing process and the pressurization process are collectively set as a set of setting conditions. The mold closing start position, the movement speed change position, the mold closing end position, and the mold closing / clamping position are arranged in that order from a back side to the front side and indicate the start and end points of sections in which the movement speeds are set. The movement speed is set for each section.A movement speed switch position may be set, or multiple movement speed switch positions may be set. It is possible that the movement speed switch position is not set. It is possible that only one of the mold closing / clamping position and mold closing / clamping force is set.

[0037] Setting conditions for the pressure release and mold opening processes are also set collectively in the same way. For example, the movement speeds and positions (including the mold opening start position, the movement speed change position, and the mold opening end position) of the crosshead 151 are set collectively as a set of setting conditions for both the pressure release and mold opening processes. The mold opening start position, the movement speed change position, and the mold opening end position are arranged in that order from front to back and indicate the start and end points of sections where the movement speeds are set. The movement speed is set for each section.A movement speed switch position may be set, or multiple movement speed switch positions may be set. It is also possible that the movement speed switch position is not set. The mold opening start position and the mold closing end position may be the same. Furthermore, the mold opening end position and the mold closing start position may be the same.

[0038] The movement speeds, positions, and the like of the movable plate 120 can be set instead of the movement speeds, positions, and the like of the crosshead 151. Furthermore, a form-closing / clamping force can be set instead of the position (for example, the form-closing / clamping position) of the crosshead or the position of the movable plate.

[0039] The toggle lever mechanism 150 amplifies the drive force of the form-closing / clamping motor 160 and transmits the amplified drive force to the movable plate 120. The amplification factor of the toggle lever mechanism 150 is also referred to as a toggle lever factor. The toggle lever factor changes depending on an angle θ between the first and second connecting links 152 and 153 (hereinafter also referred to as a "connecting link angle θ"). The connecting link angle θ is obtained from the position of the crosshead 151. In a case where the connecting link angle θ is 180°, the toggle lever factor is at its maximum.

[0040] In a case where the thickness of the mold unit 800 is changed due to replacing the mold unit 800, changing its temperature, or the like, a mold space is adjusted to maintain a predetermined mold closing / clamping force during mold closing / clamping. When adjusting a mold space, the distance L between the stationary plate 110 and the toggle lever support 130 is adjusted so that the link angle θ of the toggle lever mechanism 150 is a predetermined angle at the point of mold contact, for example, when the moving mold 820 contacts the stationary mold 810.

[0041] The mold clamping unit 100 includes a mold cavity adjustment mechanism 180. The mold cavity adjustment mechanism 180 adjusts the distance L between the stationary plate 110 and the toggle lever support 130 to adjust a mold cavity. One point in time at which a mold cavity is adjusted is, for example, between the end of one molding cycle and the start of the next molding cycle. The mold cavity adjustment mechanism 180 includes, for example, spindle shafts 181 formed at the rear end sections of the columns 140, spindle nuts 182 rotatably held by the toggle lever support 130 so that they are unable to move forwards and backwards, and a mold cavity adjustment motor 183 that rotates the spindle nuts 182 screwed onto the spindle shafts 181.

[0042] The spindle shaft 181 and the spindle nut 182 are provided for each column 140. A rotary drive force from the mold space adjustment motor 183 can be transmitted to several spindle nuts 182 via a rotary drive force transmission unit 185. The several spindle nuts 182 can be rotated synchronously. It is also possible to rotate the several spindle nuts 182 individually by changing the transmission channel of the rotary drive force transmission unit 185.

[0043] The rotary drive force transmission unit 185 contains, for example, gears and the like. In this case, a driven gear is formed on an outer circumference of each spindle nut 182, a driving gear is mounted on an output shaft of the mold space adjustment motor 183, and an intermediate gear, which engages with the several driven gears and the driving gear, is rotatably held on a central section of the toggle lever carrier 130. The rotary drive force transmission unit 185 can contain a belt, pulleys, and the like instead of gears.

[0044] The actuation of the mold space adjustment mechanism 180 is controlled by the control device 700. The control device 700 drives the mold space adjustment motor 183 to rotate the spindle nuts 182. As a result, the position of the toggle lever carrier 130 is adjusted relative to the columns 140, thus adjusting the distance L between the stationary plate 110 and the toggle lever carrier 130. Several mold space adjustment mechanisms can be used in combination.

[0045] The distance L is measured using a mold space adaptation motor encoder 184. The mold space adaptation motor encoder 184 measures the rotational magnitude and direction of the mold space adaptation motor 183 and sends signals indicating the detection results to the control device 700. The detection results of the mold space adaptation motor encoder 184 are used to monitor and control the position of the toggle lever carrier 130 and the distance L. A toggle lever carrier position detector for measuring the position of the toggle lever carrier 130 and a distance detector for measuring the distance L are not limited to the mold space adaptation motor encoder 184, and general-purpose detectors can be used.

[0046] The mold clamping unit 100 can include a mold temperature control unit that adjusts the temperature of the mold unit 800. The mold unit 800 contains a flow channel for a temperature control medium. The mold temperature control unit adjusts the temperature of the temperature control medium supplied to the flow channel of the mold unit 800 to regulate the temperature of the mold unit 800.

[0047] The form-closing / clamping unit 100 of the present embodiment is of a horizontal type, in which a form opening / closing direction is a horizontal direction, but can be of a vertical type, in which a form opening / closing direction is a vertical direction.

[0048] The mold clamping unit 100 of the present embodiment includes the mold clamping motor 160 as a drive unit, but may include a hydraulic cylinder instead of the mold clamping motor 160. Furthermore, the mold clamping unit 100 may include a linear motor for opening and closing the mold, and it may include an electromagnet for closing / clamping the mold. (Ejector unit)

[0049] In the description of the ejector unit 200, the direction of movement of the movable plate 120, as in the description of the mold closing / clamping unit 100, corresponds to a front side in a case where the mold is to be closed (for example, the positive X-axis direction), and the direction of movement of the movable plate 120 in a case where the mold is to be opened (for example, the negative X-axis direction) corresponds to a back side.

[0050] The ejector unit 200 is attached to the movable plate 120 and moves back and forth together with the movable plate 120. The ejector unit 200 contains ejector rods 210, which eject the molded products from the molding unit 800, and a drive mechanism 220, which moves the ejector rods 210 in the direction of movement of the movable plate 120 (X-axis direction).

[0051] The ejector rods 210 are arranged in through holes in the movable plate 120 such that they are able to move forwards and backwards. The front end sections of the ejector rods 210 are in contact with an ejector plate 826 of the movable mold 820. The front end sections of the ejector rods 210 may be connected to the ejector plate 826, or they may not be connected to it.

[0052] The drive mechanism 220, for example, includes an ejector motor 240 and a motion conversion mechanism that converts a rotary motion of the ejector motor 240 into a linear motion of the ejector rods 210. The motion conversion mechanism includes a spindle shaft and a spindle nut screwed onto the spindle shaft. Balls or rollers can be inserted between the spindle shaft and the spindle nut.

[0053] The ejector unit 200 performs an ejection process under the control of the control device 700. During the ejection process, the ejector rods 210 are caused to move forward at a set speed from a ready position to an ejection position, causing the ejector plate 826 to move forward to eject the molded products. Subsequently, the ejector motor 240 is driven to cause the ejector rods 210 to move backward at a set speed, causing the ejector plate 826 to move backward to its original ready position.

[0054] The position and speed of movement of each ejector rod 210 are measured, for example, using an ejector motor encoder. The ejector motor encoder measures the rotation of the ejector motor 240 and sends a signal indicating a detection result to the control device 700. An ejector rod position detector for measuring the position of each ejector rod 210 and an ejector rod speed detector for measuring the speed of movement of each ejector rod 210 are not limited to the ejector motor encoder, and general-purpose detectors can be used. (Injection unit)

[0055] In the description of the injection unit 300, in contrast to the description of the mold closing / clamping unit 100 and the description of the ejector unit 200, a direction of movement of a screw 330 during filling (for example the negative X-axis direction) corresponds to a front side, and a direction of movement of the screw 330 during metering (for example the positive X-axis direction) corresponds to a back side.

[0056] The injection unit 300 is installed on a sliding base 301, and the sliding base 301 is arranged so that it is able to move forward and backward relative to the injection unit frame 920. The injection unit 300 is arranged so that it is able to move forward and backward relative to the molding unit 800. The injection unit 300 contacts the molding unit 800 and fills the cavity spaces 801 formed in the molding unit 800 with a molding material.The injection unit 300 includes, for example, a cylinder 310 that heats the molding material, a nozzle 320 provided at a front end section of the cylinder 310, the screw 330 which is arranged in the cylinder 310 in such a way that it is able to move forwards and backwards and is rotatable, a metering motor 340 which rotates the screw 330, an injection motor 350 which causes the screw 330 to move forwards and backwards, and a load detector 360 which measures a load transmitted between the injection motor 350 and the screw 330.

[0057] The cylinder 310 heats the molding material supplied to its interior via a feed port 311. The molding material contains, for example, a resin or similar substance. The molding material is, for example, in the form of pellets and is supplied to the feed port 311 in a solid state. The feed port 311 is located at the rear of the cylinder 310. A cooler 312, such as a water-cooling cylinder, is located on the outer circumference of the rear of the cylinder 310. Initial heating elements 313, such as belt heaters, and initial temperature measuring devices 314 are located on the outer circumference of the cylinder 310 upstream of the cooler 312.

[0058] The cylinder 310 is divided into several zones along its axial direction (for example, the X-axis direction). The first heating unit 313 and the first temperature measuring device 314 are provided in each of the zones. A set temperature is configured in each zone, and the control device 700 controls the first heating units 313 so that the temperatures measured by the first temperature measuring devices 314 reach the set temperatures.

[0059] The nozzle 320 is located at the front end section of the cylinder 310 and is pressed against the molding unit 800. Second heating units 323 and second temperature measuring devices 324 are located on the outer circumference of the nozzle 320. The control device 700 controls the second heating units 323 so that the measuring temperature of the nozzle 320 reaches a set temperature.

[0060] The screw 330 is arranged in the cylinder 310 such that it is capable of moving forwards and backwards and is rotatable. When the screw 330 is rotated, a molding material is conveyed forwards along a helical groove of the screw 330. The molding material is gradually melted by heat from the cylinder 310 as it is conveyed forwards. When the liquid molding material is conveyed to the front of the screw 330 and accumulates in the front section of the cylinder 310, the screw 330 is caused to move backwards. Subsequently, when the screw 330 is caused to move forwards, the liquid molding material accumulated in front of the screw 330 is injected from the nozzle 320, and the molding unit 800 is filled with the molding material.

[0061] A non-return valve ring 331 is attached to a front section of the screw 330 in such a way that it is able to move forward and backward as a non-return valve, preventing the backflow of the molding material that flows backward from the front of the screw 330 in a case where the screw 330 is pushed forward.

[0062] In a case where the screw 330 is caused to move forward, the non-return ring 331 is pushed backward by the pressure of the molding material accumulated in front of the screw 330 and moves backward relative to the screw 330 to a closed position (see Fig. 2), where the flow channel for a molding material is closed. Accordingly, the molding material accumulated in front of the screw 330 is prevented from flowing to the rear.

[0063] On the other hand, in a case where the screw 330 is rotated, the backflow prevention ring 331 is pushed forward by the pressure of the molding material conveyed along the spiral groove of the screw 330 and moves forward relative to the screw 330 to an opening position (see Fig. 1), where the flow channel for a molding material is opened. Accordingly, the molding material is conveyed to the front of the screw 330.

[0064] The backflow prevention ring 331 can be either a rotating type, which is rotated together with the screw 330, or a non-rotating type, which is not rotated together with the screw 330.

[0065] The injection unit 300 can contain a drive source that causes the backflow prevention ring 331 to move back and forth between the open position and the closed position with respect to the screw 330.

[0066] The metering motor 340 rotates the screw 330. A drive source that rotates the screw 330 is not limited to the metering motor 340 and can, for example, be a hydraulic pump or the like.

[0067] The injection motor 350 causes the screw 330 to move forwards and backwards. A motion conversion mechanism, which converts a rotary motion of the injection motor 350 into a linear motion of the screw 330, is provided between the injection motor 350 and the screw 330. The motion conversion mechanism includes, for example, a spindle shaft and a spindle nut screwed onto the spindle shaft. Balls, rollers, or the like may be provided between the spindle shaft and the spindle nut. A drive source that causes the screw 330 to move forwards and backwards is not limited to the injection motor 350 and may, for example, be a hydraulic cylinder or the like.

[0068] The load detector 360 measures a load transmitted between the injection motor 350 and the screw 330. The measured load is converted into a pressure by the control device 700. The load detector 360 is located in a transmission channel for a load between the injection motor 350 and the screw 330 and measures the load acting on the load detector 360.

[0069] The load detector 360 sends a signal of the measured load to the control device 700. The load measured by the load detector 360 is converted into a pressure acting between the screw 330 and the molding material and is used to control and monitor a pressure received by the screw 330 from the molding material, a back pressure acting on the screw 330, a pressure acting from the screw 330 on the molding material, and the like.

[0070] A pressure detector that measures the pressure of the molding material is not limited to the 360 ​​load detector; a general-purpose detector can be used. For example, a nozzle pressure sensor or a mold cavity pressure sensor can be used. The nozzle pressure sensor is installed in the 320 nozzle. The mold cavity pressure sensor is installed in the 800 mold unit.

[0071] The injection unit 300 performs a dosing process, a filling process, a pressure maintenance process, and the like, under the control of the control device 700. The filling process and the pressure maintenance process can also be collectively referred to as an injection process.

[0072] In the dosing process, the dosing motor 340 is driven to rotate the screw 330 at a set speed, conveying the molding material forward along the helical groove of the screw 330. The molding material is thus gradually melted. When the liquid molding material is conveyed to the front of the screw 330 and accumulates in the front section of the cylinder 310, the screw 330 is caused to move backward. The rotational speed of the screw 330 is measured, for example, using a dosing motor encoder 341. The dosing motor encoder 341 measures the rotation of the dosing motor 340 and sends a signal indicating a detection result to the control device 700. A screw speed detector that measures the rotational speed of the screw 330 is not limited to the dosing motor encoder 341, and a general-purpose detector can be used.

[0073] During the dosing process, the injection motor 350 can be driven to exert a set back pressure on the screw 330 to limit its sudden reverse movement. The back pressure applied to the screw 330 is measured, for example, using the load detector 360. The dosing process is complete when the screw 330 has reversed to a dosing end position and a predetermined amount of molding material has accumulated in front of the screw 330.

[0074] The positions and speeds of the 330 screw during the metering process are collectively set as a series of parameters. For example, a metering start position, a speed changeover position, and a metering end position are set. These positions are arranged in that order from the front to the back and indicate the start and end points of sections where the speeds are set. The speed is set for each section. There may be one speed changeover position set, or there may be multiple speed changeover positions set. It is also possible that the speed changeover position is not set. Furthermore, a back pressure is set for each section.

[0075] During the filling process, the injection motor 350 is driven to cause the screw 330 to move forward at a set speed and fill the cavity spaces 801 formed in the molding unit 800 with the liquid molding material accumulated in front of the screw 330. The position and speed of the screw 330 are measured, for example, using an injection motor encoder 351. The injection motor encoder 351 measures the rotation of the injection motor 350 and sends a signal indicating the detection result to the control device 700. When the screw 330 reaches a set position, the filling process is switched to the pressure holding process (so-called V / P switching). A position at which V / P switching is performed is also referred to as a V / P switching position.The set movement speed of the screw 330 can be changed depending on the position of the screw 330, a time or the like.

[0076] The positions and speeds of screw 330 during the filling process are collectively set as a series of parameters. For example, a filling start position (also referred to as an "injection start position"), a speed changeover position, and a V / P changeover position are set. These positions are arranged in that order from back to front and indicate the start and end points of sections where the speeds are set. The speed is set for each section. There may be one speed changeover position set, or there may be multiple speed changeover positions set. It is also possible that the speed changeover position is not set.

[0077] For each section where the screw 330's travel speed is set, an upper limit for the screw 330's pressure is defined. The screw 330's pressure is measured by the load detector 360. If the screw 330's pressure is equal to or lower than the set pressure, the screw 330 moves forward at the set speed. Conversely, if the screw 330's pressure exceeds the set pressure, the screw 330 moves forward at a lower speed than the set speed to protect the mold, ensuring that the screw 330's pressure is equal to or lower than the set pressure.

[0078] Once the screw 330 has reached the V / P switching position during the filling process, it can be temporarily stopped at the V / P switching position, and the V / P switching can then be performed. Immediately before the V / P switching, instead of stopping, the screw 330 can move forward or backward at a very low speed. Furthermore, a screw position detector for measuring the position of the screw 330 and a screw speed detector for measuring the speed of movement of the screw 330 are not limited to the injection motor encoder 351, and general detectors can be used.

[0079] During the pressure-holding process, the injection motor 350 is driven to push the screw 330 forward to maintain the pressure of the molding material at a front end section of the screw 330 (hereinafter also referred to as a "holding pressure") at a set pressure, and to push any molding material remaining in the cylinder 310 toward the molding unit 800. An insufficient amount of molding material due to cooling shrinkage inside the molding unit 800 can be replenished. The holding pressure is measured, for example, using the load detector 360. A set value of the holding pressure can be changed depending on the time elapsed since the start of the pressure-holding process or similar factors. Several holding pressures and several holding times, at which the holding pressure is maintained during the pressure-holding process, can be set and can be set collectively as a set of setting conditions.

[0080] The molding material filling the cavity spaces 801 formed in the molding unit 800 is gradually cooled during the pressure holding process, and at the end of the pressure holding process, the solidified molding material closes one inlet of the cavity spaces 801. This condition is referred to as a gate seal, and it prevents the backflow of molding material from the cavity spaces 801. A cooling process is initiated after the pressure holding process. During the cooling process, the molding material in the cavity spaces 801 solidifies. The metering process can be carried out during the cooling process to shorten the molding cycle time.

[0081] The injection unit 300 of the present embodiment is of an inline screw type, but can be of a pre-plasticized type or the like. An injection unit of the pre-plasticized type feeds a molding material, which is melted in a plasticizing cylinder, to an injection cylinder and injects the molding material from the injection cylinder into a molding unit. A screw is arranged in the plasticizing cylinder such that it is rotatable and unable to move forwards and backwards, or a screw is arranged in the plasticizing cylinder such that it is rotatable and able to move forwards and backwards. Meanwhile, a plunger piston is arranged in the injection cylinder such that it is able to move forwards and backwards.

[0082] Furthermore, the injection unit 300 of the present embodiment is of a horizontal type, in which the axial direction of the cylinder 310 is horizontal, but can also be of a vertical type, in which the axial direction of the cylinder 310 is vertical. A forming clamping unit to be combined with a vertical injection unit 300 can be of either a vertical or a horizontal type. Similarly, a forming clamping unit to be combined with a horizontal injection unit 300 can be of either a horizontal or a vertical type. (Movement unit)

[0083] In the description of the motion unit 400, as in the description of the injection unit 300, the direction of movement of the screw 330 during filling (for example, the negative X-axis direction) corresponds to a front side, and the direction of movement of the screw 330 during metering (for example, the positive X-axis direction) corresponds to a back side.

[0084] The motion unit 400 causes the injection unit 300 to move back and forth relative to the molding unit 800. Furthermore, the motion unit 400 presses the nozzle 320 against the molding unit 800 to generate nozzle contact pressure. The motion unit 400 includes a hydraulic pump 410, a motor 420 as a drive source, a hydraulic cylinder 430 as a hydraulic actuator, and the like.

[0085] The hydraulic pump 410 has a first port 411 and a second port 412. The hydraulic pump 410 is a reversible pump that draws hydraulic fluid (for example, oil) from one of the first ports 411 and the second port 412 and discharges the hydraulic fluid from the other port to generate hydraulic pressure when the direction of rotation of the motor 420 is changed. The hydraulic pump 410 can also draw hydraulic fluid from a tank and discharge it from either the first port 411 or the second port 412.

[0086] Motor 420 causes hydraulic pump 410 to operate. Motor 420 drives hydraulic pump 410 in a direction of rotation corresponding to a control signal sent by control device 700, with torque corresponding to the control signal. Motor 420 can be an electric motor or an electric servo motor.

[0087] The hydraulic cylinder 430 comprises a cylinder body 431, a piston 432, and a piston rod 433. The cylinder body 431 is attached to the injection unit 300. The piston 432 divides the interior of the cylinder body 431 into a front chamber 435 (first chamber) and a rear chamber 436 (second chamber). The piston rod 433 is attached to the stationary plate 110.

[0088] The front chamber 435 of the hydraulic cylinder 430 is connected to the first port 411 of the hydraulic pump 410 via a first flow channel 401. When hydraulic fluid discharged from the first port 411 is supplied to the front chamber 435 via the first flow channel 401, the injection unit 300 is pushed forward. As the injection unit 300 moves forward, the nozzle 320 is pressed against the stationary form 810. The front chamber 435 acts as a pressure chamber, generating the nozzle contact pressure of the nozzle 320 with the pressure of the hydraulic fluid pumped by the hydraulic pump 410.

[0089] On the other hand, the rear chamber 436 of the hydraulic cylinder 430 is connected to the second port 412 of the hydraulic pump 410 via a second flow channel 402. When hydraulic fluid discharged from the second port 412 is supplied to the rear chamber 436 of the hydraulic cylinder 430 via the second flow channel 402, the injection unit 300 is pushed backward. The injection unit 300 moves backward, separating the nozzle 320 from the stationary form 810.

[0090] In the present embodiment, the motion unit 400 includes the hydraulic cylinder 430, but the present invention is not limited to this. For example, an electric motor and a motion conversion mechanism that converts a rotary motion of the electric motor into a linear motion of the injection unit 300 can be used instead of the hydraulic cylinder 430. (Control device)

[0091] The control device 700 is, for example, formed from a computer and includes a central processing unit (CPU) 701, a storage medium 702, such as a memory, an input interface 703 and an output interface 704, as in Fig. 1 and Fig. Figure 2 shows that the control device 700 causes the CPU 701 to execute a program stored in the memory medium 702 in order to perform various types of control. Furthermore, the control device 700 receives a signal from the outside via the input interface 703 and transmits a signal to the outside via the output interface 704.

[0092] The control device 700 repeatedly executes the dosing process, the mold closing process, the pressurizing process, the mold closing / clamping process, the filling process, the pressure holding process, the cooling process, the pressure release process, the mold opening process, the ejection process, and the like to repeatedly produce molded products. A series of operations to obtain molded products, for example, operations from the start of one dosing process to the start of the next dosing process, is also referred to as a "shot" or a "mold cycle." Furthermore, the time required for a shot is also referred to as a "mold cycle time."

[0093] A mold cycle, for example, includes the dosing process, the mold closing process, the pressurization process, the mold clamping / closing process, the filling process, the pressure holding process, the cooling process, the pressure release process, the mold opening process, and the ejection process, in that order. The sequence mentioned here is the order in which the respective processes are started. The filling process, the pressure holding process, and the cooling process are carried out during the mold clamping / closing process. The start of the mold clamping / closing process can coincide with the start of the filling process. The completion of the pressure release process coincides with the start of the mold opening process.

[0094] Several processes can be performed simultaneously to shorten a mold cycle time. For example, a dosing process can be performed during a cooling process of a previous mold cycle, or it can be performed during a mold closing / clamping process. In this case, the mold closing process can be performed at the beginning of the mold cycle. Furthermore, the filling process can be started during the mold closing process. Additionally, the ejection process can be started during the mold opening process. In a case where an on / off valve is provided for opening and closing a flow channel of the nozzle 320, the mold opening process can be started during the dosing process. The reason for this is that no mold material will exit the nozzle 320 as long as the on / off valve closes the flow channel of the nozzle 320, even if the mold opening process is started during the dosing process.

[0095] A mold cycle can include processes that differ from the dosing process, the mold closing process, the pressurizing process, the mold closing / clamping process, the filling process, the pressure holding process, the cooling process, the pressure relief process, the mold opening process, and the ejection process.

[0096] For example, after the pressure holding process is complete, a back-suction process can be performed before dosing to cause the screw 330 to move backward to a preset dosing start position. Since the pressure of the molding material accumulated in front of the screw 330 can be reduced before the start of the dosing process, the sudden backward movement of the screw 330 at the start of the dosing process can be prevented.

[0097] Furthermore, after the dosing process is complete, a post-dosing vacuuming process can be performed to cause the screw 330 to move backward to a preset filling start position before the filling process begins. Since the pressure of the molding material accumulated in front of the screw 330 can be reduced before the filling process starts, the exit of the molding material from the nozzle 320 before the filling process begins can be prevented.

[0098] The control device 700 is connected to an operating unit 750, which receives user input, and to a display unit 760, which displays a screen. The operating unit 750 and the display unit 760 can, for example, be formed from a touch panel 770 and can be integrated together. The touch panel 770, as the display unit 760, displays a screen below the control device 700. Information such as the settings and current status of the injection molding machine 10 can be displayed on the touch panel 770 screen. Furthermore, the touch panel 770 screen can display operating elements, such as buttons or input fields, which are used to receive user input.The touch panel 770, acting as the control unit 750, detects user input on the screen and sends a corresponding signal to the control device 700. Accordingly, a user can, for example, operate the control section provided on the screen to set the injection molding machine 10 (including entering a setting value) while reviewing information displayed on the screen. Furthermore, a user can operate the control section provided on the screen to initiate the operation of the injection molding machine 10 corresponding to that section. The operation of the injection molding machine 10 could, for example, include the operation (including stopping) of the mold clamping unit 100, the ejector unit 200, the injection unit 300, the motion unit 400, or the like.Furthermore, the operation of the injection molding machine 10 may involve switching the screen displayed on the touch panel 770 as the display unit 760, or the like. (Safety function)

[0099] Furthermore, as indicated by two-dot dash lines in Fig. 1 and Fig. Figure 2 shows that the injection molding machine 10 has a housing 940 that covers the mold clamping unit 100, the ejector unit 200, and the mold unit 800. The housing 940 serves a protective function, preventing the operator of the injection molding machine 10 from coming into contact with the mold unit 800 or similar components during injection molding. The housing 940 can be configured to cover up to the injection unit 300 or to cover the entire injection molding machine 10.

[0100] For example, the housing 940 is formed in a rectangular shape (box shape) and is attached to an upper surface of the frame 900 (form-closing / clamping unit frame 910). A nozzle section (not shown), through which the cylinder 310 and the nozzle 320 of the injection unit 300 can move forwards and backwards, is provided on a side surface of the housing 940 in the positive X-axis direction.

[0101] The enclosure 940 has one or more safety doors 941 which can be opened and closed by the user. Fig. 1 and Fig. Figure 2 shows an example where the safety door 941 is installed on the side surface of the housing 940 on the positive side in the Y-axis direction (front side of a paper surface). However, the installation position of the safety door 941 is not particularly restricted and it can be a side surface in a negative Y-axis direction, a side surface in the negative X-axis direction, or a top surface in a positive Z-axis direction. The safety door 941 can be of any single-opening type, a sliding type, or a double-opening type.

[0102] Furthermore, the injection molding machine 10 has an open / close detector 942 that detects the open and closed states of the safety door 941. The type of open / close detector 942 is not particularly restricted, and examples include those using a mechanical switch, those using an optical sensor, and the like. The open / close detector 942 is communicatively connected to a control board 710, which is provided in the interior 922 on the underside of the injection unit frame 920 in the vertical direction, and transmits information about the open and closed states of the safety door 941.

[0103] The control board 710 has a digital circuit 711 for controlling the locking of the injection molding machine 10 to ensure the safety of the injection molding machine 10. In addition, the interior 922 contains a power supply circuit 720, which supplies current to the mold closing / clamping motor 160, in addition to the control board 710.

[0104] Fig. Figure 3 is a diagram showing a main configuration of the power supply circuit 720 of the form-closing / clamping motor 160 and the control board 710. As shown in Fig. As shown in Figure 3, the digital circuit 711 of the control board 710 incorporates a programmable logic controller (hereinafter also referred to as a safety PLC 712) for controlling the locking mechanism. The safety PLC 712 is a dedicated programmable logic controller for the safety control of the injection molding machine 10, and it uses, for example, an IC chip certified by a safety standard. The digital circuit 711 is not limited to the use of the safety PLC 712, and another processor (CPU, GPU, ASIC, FPGA, or the like) can be used.

[0105] In addition to the safety PLC 712, the control board 710 contains an input / output interface 713, a memory (not shown), and similar components. The control board 710 is connected to the opening and closing detector 942 of the safety door 941 via the input / output interface 713.

[0106] A signal output by the opening and closing detector 942 contains information about the open and closed state of the safety door 941. If the safety door 941 is opened during injection molding on the injection molding machine 10, there is a possibility that the user could come into contact with the mold closing / clamping unit 100 or the mold unit 800, which performs the mold closing / clamping. For this reason, the safety PLC 712 ensures safety by interrupting the power supply to the mold closing / clamping motor 160 to limit movement of the mold closing / clamping unit 100, thus controlling the locking mechanism.

[0107] This means that information about the opening of safety door 941 during injection molding on injection molding machine 10 constitutes a trigger signal for the urgent stop of injection molding machine 10. The stop trigger signal is not limited to information about the opening of safety door 941 and can include various types of information. For example, other examples of the stop trigger signal include information about the opening of a safety cover or a flushing cover, which covers a suitable configuration of injection molding machine 10, and information about the activation of an emergency stop button on injection molding machine 10. Alternatively, the stop trigger signal can be information about the occurrence of an abnormality, output by a processing substrate (for example, the control device 700), which diagnoses the occurrence of the abnormality in injection molding machine 10.In other words, the opening and closing detector 942 of the safety door 941, the opening and closing detector of the safety cover or the flushing cover, the emergency stop button or the control device 700 forms a trigger generation unit 943 (see . Fig. 4), which is capable of generating the trigger signal. The control board 710 is connected to each configuration of the trigger generation unit 943 via the input / output interface 713.

[0108] Meanwhile, the power supply circuit 720, for example, electrically connects the interior 922 of the injection unit frame 920 and the mold clamping motor 160, which is installed above the mold clamping unit frame 910. Specifically, the power supply circuit 720 includes a drive unit 721, several wires 722 connecting the drive unit 721 and the mold clamping motor 160, and a changeover switch 730 that switches the power supply and power supply cutoff to the mold clamping motor 160 at an intermediate position of the several wires 722. Furthermore, the power supply circuit 720 includes a power supply detection unit 723 that detects current (for example, a current) being supplied to the mold clamping motor 160 at the intermediate position of the several wires 722.

[0109] For example, it is preferred that an AC servomotor, driven by a three-phase AC power supply, is connected to the mold clamping / spinning motor 160. Accordingly, the mold clamping / spinning motor 160 can accurately control a rotation angle or speed, and the mold clamping / spinning unit 100 can be positioned with high accuracy. Furthermore, the type of motor used in the mold clamping / spinning motor 160 is not particularly restricted and can be another servomotor, a stepper motor, or the like.

[0110] The drive unit 721 of the power supply circuit 720 has a suitable configuration according to the type of the form-closing / clamping motor 160. For example, in a case where the form-closing / clamping motor 160 is the AC servo motor, the drive unit 721 is connected to a U-phase wire 722u, a V-phase wire 722v, and a W-phase wire 722w. The drive unit 721 outputs the three-phase AC power to the form-closing / clamping motor 160 via each of these wires 722.

[0111] The drive unit 721 is connected to a controller 724, which outputs a control pulse, and is connected to a power supply unit 725 of the injection molding machine 10. The controller 724 is connected to the control device 700, receives a control command from the control device 700, and outputs the control pulse to the drive unit 721 based on the control command. The drive unit 721 includes a current conversion unit 721a, such as a converter or inverter (not shown), a current matching unit 721b, and the like, and adjusts the current supplied by the power supply unit 725 based on the input control pulse to output the current to the mold closing / clamping motor 160.

[0112] In addition, the power supply detection unit 723 detects an actual current supplied by the form-closing / clamping motor 160 in the U-phase wire 722u and the V-phase wire 722v and returns detection information of it to the current matching unit 721b.

[0113] The changeover switch 730 of the power supply circuit 720 supplies current from the drive unit 721 to the form-closing / clamping motor 160 and stops the power supply. Furthermore, the changeover switch 730 has a function of switching between deactivating the brake of the form-closing / clamping motor 160 and activating the brake. Specifically, the changeover switch 730 includes an A-contact section 731, which opens and closes each of the three wires 722 at an A-contact, a B-contact section 732, which is connected to the A-contact section 731, and a switching coil 733, which switches the A-contact section 731 and the B-contact section 732 simultaneously. Furthermore, the changeover switch 730 is connected to the safety PLC 712 via the input / output interface 713 and switches the A-contact section 731 and the B-contact section 732 based on a signal from the safety PLC 712. The respective parts can be directly connected to each other.For example, the changeover switch 730 and the safety PLC 712 can be connected to each other via a relay or the like. However, the present disclosure is not limited to the direct connection of the parts to each other. Furthermore, in the present embodiment, the A-contact section 731 and the B-contact section 732 are switched simultaneously, but can be switched with a time difference in accordance with the design of the circuit. In other words, the A-contact section 731 is opened based on the receipt of a switching signal, and the B-contact section 732 is closed based on the receipt of the same switching signal. The switching time between the A-contact section 731 and the B-contact section 732 can be the same or different.

[0114] The B-contact section 732 has a switch that connects the U-phase wire 722u, the V-phase wire 722v, and the W-phase wire 722w, respectively, via a star connection on a secondary side (side of mold-closing / clamping motor 160) of the A-contact section 731. This switch opens and closes the two wires connected to the star connection at the B-contact. Furthermore, the B-contact section 732 has a resistor (not shown) at a suitable position on the star connection. In the present embodiment, the injection molding machine 10 is configured to close the B-contact section 732 after the drive of the mold-closing / clamping motor 160 has been stopped, thus reducing the resistance value (magnitude) of the resistor. The injection molding machine 10 can also be configured without the resistor.

[0115] As an example, the A-contact section 731 closes (switches on) the U-phase wire 722u, the V-phase wire 722v and the W-phase wire 722w in an excitation state of the switching coil 733, respectively, and enables power supply from the drive unit 721 to the form-closing / clamping motor 160. Meanwhile, the B-contact section 732 is open (switched off) in the excitation state of the switching coil 733.

[0116] The changeover switch 730 switches the changeover coil 733 to a non-excitation state via a changeover signal from the safety PLC 712. In this case, the A-contact section 731 opens (switches off) the U-phase wire 722u, the V-phase wire 722v, and the W-phase wire 722w respectively, thus stopping the power supply from the drive unit 721 to the form-closing / clamping motor 160. Meanwhile, the B-contact section 732 is closed (switched on) in the non-excitation state of the changeover coil 733. The B-contact section 732 shorts the terminals to which each of the wires 722 of the form-closing / clamping motor 160 is connected via the resistor. Consequently, the form-closing / clamping motor 160 dissipates rotational energy as heat, and a large braking torque is applied, thus allowing the form-closing / clamping motor 160 to be stopped quickly.This means that the switch 730 has a dynamic brake function that switches between not activating the brake of the form-closing / clamping motor 160 and activating the brake by only switching the B-contact section 732.

[0117] Fig. Figure 4 is a block diagram showing the functional blocks of the control device 700 and the safety PLC 712. The control device 700 forms functional blocks, such as a form-closing / clamping unit control unit 740, a trigger detection unit 741, a signal generation unit 742, and an abnormality diagnostic unit 743, within the control device 700, as shown in Figure 4. Fig. 4 shown by causing the CPU 701 to execute the program stored in the memory medium 702.

[0118] The mold clamping / closing unit control unit 740 controls the operation of the mold clamping / closing unit 100 during the mold cycle described above. For example, during each of the mold clamping process, the pressurization process, the mold clamping / closing process, the pressurization process, and the mold opening process, the mold clamping / closing unit control unit 740 issues a control command to the controller 724 to control the operation of the mold clamping / closing motor 160, thereby operating the mold clamping / closing motor 160 via the drive unit 721. Accordingly, the mold clamping / closing unit control unit 740 can move the movable mold 820 of the mold unit 800 to a target position during each process.

[0119] The trigger detection unit 741 detects the stop trigger signal from the trigger generation unit 943 (the opening and closing detector 942 of the safety door 941, the opening and closing detector of the safety cover or the flushing cover, the emergency stop button, or the like) and stores the stop trigger signal in the storage medium 702. In addition, the trigger detection unit 741 can detect the stop trigger signal from the abnormality diagnostic unit 743. The abnormality diagnostic unit 743 normally monitors signals from each configuration, sensor, and the like of the injection molding machine 10 to determine whether an abnormality is present. If the abnormality diagnostic unit 743 determines that an abnormality exists that requires the injection molding machine 10 to be stopped, the abnormality diagnostic unit 743 outputs the stop trigger signal to the trigger detection unit 741.

[0120] The mold clamping unit control unit 740 urgently stops the operation of the mold clamping unit 100 based on the receipt of the stop trigger signal in the trigger detection unit 741. For example, during a process in which the mold clamping unit 100 applies the clamping force to the stationary mold 810 and the moving mold 820 of the molding unit 800 (the pressurization process, the clamping process, and until the completion of the pressure release process), the mold clamping unit control unit 740 performs a pressure release operation on the mold clamping unit 100. Accordingly, in the event of an emergency stop of the mold clamping unit 100, the injection molding machine 10 can prevent the molding unit 800 from being unintentionally opened by a reaction force of the clamping force and thus prevent damage to the molding unit 800.

[0121] Furthermore, if the abnormality diagnostic unit 743 determines that an abnormality is present, the signal generation unit 742 provides the control device 700 with the information (the stop trigger signal: see dashed line in Fig. 4) to the safety PLC 712 of the control board 710.

[0122] Meanwhile, the safety PLC 712 forms a trigger detection unit 715, an operating state detection unit 716, a changeover state detection unit 717, a determination unit 718 and a changeover signal generation unit 719 therein, executing the program stored in an internal memory.

[0123] The trigger detection unit 715 detects the stop trigger signal from the trigger generation unit 943 (the opening and closing detector 942 of the safety door 941, the opening and closing detector of the safety cover or the flushing cover, the emergency stop button, the control device 700 or the like).

[0124] The operating state detection unit 716 detects a signal from the mold closing / clamping motor 160 and monitors a switch-on or switch-off signal of the mold closing / clamping motor 160. The operating state detection unit 716 can detect the current operating state (process of mold cycle, waiting, stop or the like) of the injection molding machine 10 from the control device 700 or the like.

[0125] The switch state detection unit 717 detects a position, presence or absence of fixation and the like of the switching coil 733 from a state detector (not shown) which detects a state of the switching coil 733 of the switch 730.

[0126] The control unit 718 determines whether the changeover switch 730 is operated based on the trigger signal from the trigger detection unit 715, the operating state of the injection molding machine 10 from the operating state detection unit 716, the state of the changeover switch 730 from the changeover state detection unit 717, and the like. For example, if the injection molding machine 10 is in the molding cycle (injection molding) and the stop trigger signal is received, the control unit 718 determines that the switching coil 733 of the changeover switch 730 is switched from the energized state to the unenergized state. Furthermore, the control unit 718 determines, for example, that the changeover switch 730 is not switched if the mold closing / clamping motor 160 is in the off state and the stop trigger signal is received.In the off state of the form-closing / clamping motor 160, the changeover switch 730 is already in the non-excitation state, and even if the user opens the safety door 941, the changeover switch 730 remains in the non-excitation state.

[0127] Furthermore, the switching signal generation unit 719 outputs a switching signal to the switch 730 based on the switching determination of the switch 730 via the determination unit 718. Meanwhile, the switching signal generation unit 719 waits for a preset waiting period from the time at which the determination unit 718 has made its determination (or at which the stop trigger signal has been received) and outputs the switching signal after the waiting period has elapsed. The waiting period is set to be equal to or longer than the time required to complete the pressure relief of the mold clamping unit 100 during the emergency stop described above (for example, a time slightly longer than the time required to complete the pressure relief).In this way, the safety PLC 712 outputs the changeover signal to the changeover switch 730 after the pressure relief of the mold clamping unit 100 is complete, and switches the changeover coil 733 from the energized state to the de-energized state. The changeover switch 730 can prevent the mold clamping unit 100 and the mold unit 800 from moving by stopping the power supply to the mold clamping motor 160 and activating the brake of the mold clamping motor 160. (Control processing when security door 941 is open)

[0128] The injection molding machine 10 according to the present embodiment is configured essentially as described above, and its operation is described below with reference to Fig. 5 described. Fig. Figure 5 is a timing diagram showing an operating procedure when the safety PLC 712 stops the form-closing / clamping motor 160.

[0129] The mold clamping / closing unit control unit 740 of the control device 700 outputs a control signal corresponding to each process of the mold cycle to the drive unit 721 to control the operation of the mold clamping / closing motor 160. In this case, the operating state detection unit 716 of the safety PLC 712 detects the switch-on signal, which indicates that the mold clamping / closing motor 160 is in a motor-on state.

[0130] The opening and closing detector 942 of the safety door 941 detects the opening of the safety door 941 at a time t1 during the injection molding process of the injection molding machine 10, which is located in Fig. Figure 5 is shown. In this way, the opening and closing detector 942 outputs the information about the opening of the safety door 941 as the stop trigger signal to the control device 700 and the safety PLC 712.

[0131] When the mold clamping / holding unit control unit 740 of the control device 700 receives the stop trigger signal from the trigger detection unit 741, the mold clamping / holding unit control unit 740 terminates the current mold cycle and starts a pressure relief process of reducing pressure from a state in which the mold unit 800 is pressed by the mold clamping / holding unit 100 (see a time t2 in Fig.5) In this case, the mold clamping / closing unit control unit 740 actuates the mold clamping / closing motor 160 to cause the movable mold 820 to move slightly backward away from the stationary mold 810. Accordingly, the pressure relief of the mold clamping / closing unit 100 is completed at time t3. Furthermore, the mold clamping / closing force of the mold unit 800 can be set to zero during the emergency stop pressure relief. Therefore, the stationary mold 810 and the movable mold 820 can be in contact with each other or separated from each other.

[0132] Once pressure relief is complete, the mold closing / clamping unit control unit 740 issues a power-off command to the drive unit 721 as the control command for the mold closing / clamping motor 160. Based on this control command, the drive unit 721 stops the power supply to the mold closing / clamping motor 160. If the moving mold 820 is not in contact with the stationary mold 810 during the mold cycle (the mold closing process, the mold opening process, or the like), a power-off control command can be issued to the mold closing / clamping motor 160 without performing pressure relief.

[0133] Meanwhile, the safety PLC 712 also receives the stop trigger signal from the trigger detection unit 715 at time t1 during the mold cycle. In this way, the determination unit 718 determines the opening (switching off) of each of the wires 722 between the drive unit 721 and the mold closing / clamping motor 160. The changeover signal generation unit 719 waits for the output of the changeover signal for the set waiting time based on the determination by the determination unit 718.

[0134] As a result, the switching signal generation unit 719 outputs the switching signal to the switch 730 at time t4, at which the waiting time since time t2 has elapsed. Time t4 is a time at which a period of time beyond time t3 has passed since time t2, and is a time at which the pressure relief of the mold closing / clamping unit 100 is complete.

[0135] The changeover switch 730 switches (opens) each switch of the A-contact section 731 off and switches (connects) each switch of the B-contact section 732 on, based on the receipt of the changeover signal. Accordingly, the power supply to the mold clamping motor 160 can be stopped, and the brake in the mold clamping motor 160 can be activated. At the time when the changeover switch 730 switches off the A-contact section 731 and switches on the B-contact section 732, a control command to stop the power supply is transmitted from the control device 700 to the drive unit 721, and the power supply to the drive unit 721 is reduced (for example, the power supply is zero). By stopping the power supply to the drive unit 721, the mold clamping motor 160 can easily stop its rotation.This means that if the safety door 941 is opened during injection molding, the digital circuit 711 detects the trigger signal and controls the changeover switch 730. In this way, the injection molding machine 10 can stop the mold closing / clamping motor 160 early (without a time delay) and with high accuracy after the control to stop the mold closing / clamping motor 160 has been started.

[0136] Furthermore, the brake for the mold clamping motor 160 is activated when the B-contact section 732 is switched on. Accordingly, a position can be maintained after the mold clamping motor 160 has stopped. Therefore, it is possible to limit movement of the mold clamping unit 100 or the mold unit 800 caused by the application of an external force.

[0137] As described above, the injection molding machine 10, according to the present embodiment, detects the stop trigger signal in the digital circuit 711 and controls the changeover switch 730 via the digital circuit 711 to stop the power supply to the mold clamping motor 160 and activate the brake. Accordingly, it is possible to prevent the operating time of the changeover switch 730 from varying due to variations in the parts or environmental factors, and to accurately control the stopping time of the mold clamping motor 160. In particular, in a case where the function of switching between brake deactivation and brake activation is provided using the changeover switch 730, as in the present embodiment, the braking time can be accurately controlled, and the movement of the mold clamping unit 100 or the mold unit 800 can be quickly limited.As a result, the user can safely touch the mold closing / clamping unit 100 or the mold unit 800. Furthermore, the movement of the mold unit 800 is limited. This prevents damage to the mold unit 800.

[0138] Furthermore, the injection molding machine 10 is configured to short-circuit the terminals of the mold clamping motor by switching the changeover switch 730, thereby simplifying and reducing the cost of the brake. The injection molding machine 10 also incorporates the A-contact section 731 and the B-contact section 732 into the changeover switch 730. This allows for the simultaneous transition from power supply to power cut-off of the mold clamping motor 160 and from deactivation of the brake of the mold clamping motor 160 to activation of the brake.

[0139] The safety PLC 712 of the digital circuit 711 can perform switching of the changeover switch 730 at a suitable time by waiting for the waiting period set upon receipt of the trip signal. For example, by setting the waiting period to be equal to or longer than the time required to complete the pressure relief of the mold clamping unit 100, it is possible to avoid the inconvenience of residual pressure in the mold clamping unit 100 by stopping the power supply to the mold clamping motor 160 before the pressure relief is complete.

[0140] The injection molding machine 10 of the present disclosure is not limited to the configuration mentioned above and can assume various modification examples. For example, the brake activated in the mold closing / clamping motor 160 by the switch 730 is not limited to the dynamic brake, and a configuration can be used, for example, in which the brake is capable of mechanically braking a rotary shaft of the mold closing / clamping motor 160.

[0141] For example, according to the present embodiment, the safety PLC 712 is configured to wait for the completion of pressure relief by the mold clamping unit 100 before receiving the stop trigger signal in order to switch the changeover switch 730. However, the safety PLC 712 can be configured to switch the changeover switch 730 based on receiving a signal from the control device 700 indicating completion of pressure relief, without counting the waiting time. In this way, the injection molding machine 10 can switch the changeover switch 730 after the completion of pressure relief and can also switch the changeover switch 730 immediately in a case where the mold clamping unit 100 does not perform pressure relief.

[0142] The injection molding machine 10 according to the embodiments disclosed herein is merely an example and is in no way limiting. The embodiments can be modified and improved in various ways without deviating from the appended claims and the scope of protection of the claims. The elements described in the various embodiments can include other components within a consistent range and can be combined within a consistent range. Brief description of the reference symbols 10 injection molding machines 100 Form-fit / clamping units 160 Form-closing / clamping motor 700 Control device 711 digital circuit 712 Safety PLC 721 Drive unit 722 wire 730 switches 731 A-Contact section 732 B-contact section 800 molding units

Claims

[1] Injection molding machine (10), comprising: a mold closing / clamping motor (160) that moves a mold closing / clamping unit (100) to perform mold closing / clamping of a mold unit (800); a drive unit (721) that supplies power to the form-closing / clamping motor (160); a changeover switch (730) provided in a wire (722) connecting the mold closing / clamping motor (160) and the drive unit (721), which is capable of switching between supplying and stopping the current from the drive unit (721) to the mold closing / clamping motor (160), and which is capable of switching between not activating a brake of the mold closing / clamping motor (160) and activating the brake; and a digital circuit (711) connected to the changeover switch (730) and controlling the changeover switch (730), wherein the digital circuit (711) controls the changeover switch (730) based on the detection of a trigger signal to stop the mold closing / clamping motor (160) in order to perform the feed stop and activation of the brake, the digital circuit (711) controls the feed stop of the switch (730) and the activation of the brake after waiting for a waiting period that is set from the time at which the trigger signal is detected, and The waiting time is set to be equal to or longer than the time in which pressure relief is completed from a state in which the forming unit (800) is pressed by the forming closing / clamping unit (100). [2] Injection molding machine (10) according to claim 1, wherein the changeover switch (730) short-circuits terminals of the mold closing / clamping motor (160) on the basis of receiving a changeover signal from the digital circuit (711) to activate the brake. [3] Injection molding machine (10) according to claim 2, wherein the changeover switch (730) includes an A-contact section (731) which opens and closes the wire (722) via an A-contact, and a B-contact section (732) which opens and closes via a B-contact between the terminals of the form-closing / clamping motor (160), and The switch (730) opens the A contact section (731) based on the reception of the switching signal and closes the B contact section (732) based on the reception of the same switching signal. [4] Injection molding machine (10) according to one of claims 1 to 3, wherein the digital circuit (711) controls the feed stop of the changeover switch (730) and the activation of the brake based on receiving a signal of completion of pressure relief from a control device (700) that controls the mold closing / clamping unit (100). [5] Injection molding machine (10) according to one of claims 1 to 3, wherein the digital circuit (711) includes a PLC (712) which processes the trigger signal to control the switch (730).

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